Transforming growth factor-β (TGF-β) promotes the expression of plasminogen activator inhibitor-1 (PAI-1), and then PAI-1 promotes fibrosis and regulates degradation of fibrin and stromal adhesion of lung fibroblasts by affecting pericellular plasminase activity, which results in IPF [104]. This evidence concerns the gene SERPINE1 and idiopathic pulmonary fibrosis.